23 lines
927 B
Forth
23 lines
927 B
Forth
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// https://www.shadertoy.com/view/4dcSRX
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// https://www.shadertoy.com/view/MslGR8
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// https://www.shadertoy.com/view/Md3XRf *
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// note: valve edition from http://alex.vlachos.com/graphics/Alex_Vlachos_Advanced_VR_Rendering_GDC2015.pdf
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// note: input in pixels (ie not normalized uv)
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uniform float intensity = 250.0; // [2..255]
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vec3 ScreenSpaceDither2(vec2 vScreenPos, float colorDepth) {
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// lestyn's RGB dither (7 asm instructions) from Portal 2 X360, slightly modified for VR
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vec3 vDither = vec3(dot(vec2(131.0, 312.0), vScreenPos.xy + iTime));
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vDither.rgb = fract(vDither.rgb / vec3(103.0, 71.0, 97.0)) - vec3(0.5, 0.5, 0.5);
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return (vDither.rgb / colorDepth) * 0.375;
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}
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void mainImage( out vec4 fragColor, in vec2 fragCoord ) {
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vec2 uv = fragCoord.xy / iResolution.xy;
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vec4 color = texture(iChannel0, uv);
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fragColor = color + vec4(ScreenSpaceDither2(gl_FragCoord.xy,255.0 - intensity), 0);
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}
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